DOVER, Del. (AP) Cole Custer raced to his seventh Xfinity Series victory of the season Saturday at Dover International Speedway.

The 21-year-old Custer, who made his 100th start, proved as a top contender for the title as NASCAR's second-tier series gets set to move into the next round of the playoffs. Custer started from the pole in the No. 00 Ford for Stewart-Haas Racing and led 31 laps to win for the time since August.

"I wanted to win here so bad for so long," Custer said.

Custer, Christopher Bell and Tyler Reddick have combined to win 19 of the 29 Xfinity Series races. Bell and Reddick are each making the move to the Cup Series next year, while Custer's future is uncertain.

"It is what it is," Custer said.

Dover also marked the first cutoff race in the Xfinity Series and John Hunter Nemechek, Brandon Jones, Ryan Sieg and Justin Haley were knocked out from championship contention.

"We just haven't been able to close this year," Nemechek said. "I feel like that's been one of our struggles."

Jones had his bid to race his way into the second round spoiled on an accident in the opening lap.

"I always try to find the positives with this kind of stuff," Jones said. "None today."

Custer, Bell and Reddick are joined in the next round by Michael Annett, Justin Allgaier, Noah Gragson, Austin Cindric, and Chase Briscoe.

Allgaier won the first two stages and finished second at Dover, followed by Cindric, Haley and Briscoe.

"That is two weeks in a row I feel like we had the best race car and didn't get the win," said Briscoe, who led 71 laps. "There are so many circumstances that go into winning these races and one little thing that you don't catch at the right time just kills you."

The next round starts in two weeks at Kansas Speedway.

"Going into Kansas and Texas, we just know that we're going to fire on all cylinders and we can go in there and win," Custer said.